Longline vessels have distinctive vessel tracks—these reflect the setting and hauling of the vessel’s fishing gear. The setting of lines is done more quickly than the hauling.
Buoys are often associated with longline vessels and the buoys' movements can display characteristic tracks as the longlines are deployed and then hauled in.
Try it out: See the detailed fishing movement of a Chinese longline vessel and its buoys near the Marshall Islands.
Buoy locations can be particularly useful for vessel movement analysis when there is limited AIS reporting from the vessel itself.
Even when longline vessels move in less methodical patterns, looping tracks with variable speeds, as the lines are set and hauled are still evident.
Learn more: The MCS Practitioners Introductory Guide to Longline Fishing, developed by Trygg Mat Tracking (TMT) in cooperation with the International MCS Network (IMCSN; MCS means monitoring control and surveillance) and Francisco Blaha, provides detailed information on longline fishing as well as further information on longline vessel tracks observed in AIS and VMS.